Slalom water ski



Jan. 9, 1962 P. R. FRANKE 3,015,831

sLALoM WATER SKI Filed Feb. 20, 1958 llllllllllllll INVENTOR. PH\L\P R.FRANKE.

BY MM r M ATTORNEYS United States Patent Filed Feb. 20, 1958, Ser.'N0.716,366 Claims. (Cl. 9-310) This invention relates to water skis, andmore particularly to the type known as the slalom ski.

The sport of water skiing was developed rapidly in the last few years inthis country with the advent of smaller, faster and more powerfulmotorboats, capable of a speed sufiicient to permit the relatively smallskis to support a skier on the water. Water skiing is an outgrowth ofpowered surfboard riding wherein a comparatively large board is used tosupport the rider.

With the advent of increasingly powerful motive equipment water skiersfound it possible to ride along on two skis and then to discard one ofthem, staying up on the remaining single ski. This skiing on a singleski has caused the development of a line of skis especially formed forsingle skiing. With this later ski, the skier starts off initially withbut one ski, and does not discard one in motion. This single ski is of afairly broad construction and relatively rigid, and it is fitted withbindings to take both of the feet of the skier.

The principal difference between the double and the single skioperations is that with the single ski it is possible to maneuver morequickly. This permits the skier to re peatedly cross back and forthacross the wake of the boat and to make high speed turns with moresafety. In the case of skiing on exhibition, or as a part of a show,this increased maneuverability is important.

In the past, water skis have been built with parallel sides and squarestems, or relatively straight sides to approximately the center line andthen tapering sharply to the stem, or skis which were relatively wide inthe center and tapered sharply both to the bow and to the stern.

My improved slalom ski has several advantages over any of the otherforms of skis previously available. It is possible with this ski to getto planing speed much quicker than with any of the earlier forms ofskis. The shape of the ski cuts the drag of the ski in the water to suchan extent that a must faster acceleration is possible. Additionally,this ski is much more maneuverable as a slalom ski than the earliermodels. This makes possible much sharper turns and much wider swingsbehind the towing boat.

In the drawings,

FIG. 1 is a plan view of a ski constructed according to my invention,and

FIG. 2 is a view in side elevation of such a ski.

A ski constructed according to this invention comprises a body portion10 which is relatively fiat from the stern 11 to a point near the how12. The how 12 of the ski is turned up to effect a planing action tokeep the bow of the ski up out of the water, as is well known. Adjacentthe stern 11 of the ski, is shown a keel or vertical stabilizer 14 whichgives lateral stability to the ski in the water. Without such a verticalstabilizer or keel, the ski would slip sideways in the water.

Bindings are provided on the upper surface 16 of the body of the ski 10to hold the ski on the feet of the skier. A forward binding consistingof a toe receiving portion 18 and a heel receiving portion 20 is locatedapproximately at the longitudinal center of the ski. The bindings 18 and20 hold the ski firmly both laterally and longitudinal-1y with respectto one of the feet of the skier.

The rear binding comprises a toe receiving portion 22, which is situatedfar enough back on the ski to permit the skier to shift his weightrearwardly to effect the 2 sudden and sharp turning which ischaracteristic of slalom skiing.

The improvement which is the subject of my invention lies in shaping theside edge of the main body 10 of the ski. It comprises forming arelatively narrow portion behind the center line of the ski. I prefer tobegin the narrowing approximately under the forward binding,approximately midway between the members 18 and 20, and to reach thenarrowest width at a point just forward of the rear binding; then tobroaden out the body of the ski to a point behind the rear binding 22before again narrowing the ski at the stern.

I prefer to shape the ski so that near the bow of the ski, at the pointA, the ski is approximately 6% inches wide. The body 10 of the ski isthen broadened out slightly so that at the point B (approximately aquarter of the length of the ski) it is approximately 8 inches wide.This dimension is maintained back to the point C which is approximatelymidway between the binding elements 18 and 20.

At point D, the width of the ski is 6% to 6 /2 inches, 1

the point D being situated approximately 12 inches from the stern of theski. The distance between points C and D is approximately 24 inches, andat the mid-point between points C and D, about one-third of the distancebetween the forward foot rest and the stern (here referred to as pointE) the ski is narrowed down to 5 to 5 A inches-its narrowest.

The effect of this narrowing of the ski at the point where the weight ofthe skier is concentrated seems to be to permit the water to flow aroundthe ski easier at this point thereby cutting down the drag.Additionally, it appears to permit quicker turns because the ski is morereadily movable laterally in the water to obtain a turning attitude onthe ski.

Having described my invention, what-I claim as new and desire to protectby Letters Patent is:

l. A single slalom water ski comprising an elongate strip of relativelyrigid material having an upturned bow at the forward end and a stern atthe rearward end with the being substantially straight from the upturnedbow to the stern, a foot rest on the top side of the 'ski'about midwaybetween the bow and the stern and arearward foot rest spaced rearwardlyof the forward foot rest but forwardly of the stern, the ski havingsubstantially flat top and bottom walls and side walls which taperoutwardly slightly from the upturned bow to a point in advance of theforward foot rest and then remain substantially parallel from said pointto about the mid-portion of the forward foot rest, and which then taperinward-1y from said mid-portion of the forward foot rest to a narrowestportion between the forward foot rest and the rearward foot rest andthen taper outwardly from said narrowest portion between said foot reststo beyond the rearward foot rest but to a point in advance of the sternof the ski.

2. A slalom water ski as claimed in claim 1 in which the outward taperedportion of the sides of the ski is followed by a portion which tapersinwardly to the stern.

3. A slalom water ski as claimed in claim 1 which includes a keelextending perpendicularly downwardly from the bottom side of the skimidway between the lateral edges and the stern.

4. A slalom water ski as claimed in claim 1 in which the narrowestportion between the rearward and forward foot rests is approximately 60percent as wide as the widest portion of the ski between the forwardfoot rest and the upturned how.

5. A slalom Water ski as claimed in claim 1 in which the narrowestportion of the ski is located approximately 3 4 one-third of thedistance between the forward foot rest FOREIGN PATENTS and the stem.804,598 France Aug. 3, 1936 References Cited in the file of this patentOTHER REFERENCES UNITED STATES PATENTS 5 General Marine Company,Speed-liner, Aquadynamic 1 559 390 Waller O 27 1925 Water Skis, receivedinto Division Feb. 21, 1957. 2,510,794 Beerli June 6, 1950

